Facilitating mobile station location using a ground-based cellular network

Abstract

Communications facilitate locating a mobile station (22) using the radio frequency spectrum typically used for cellular communications. A first locating signal is communicated between a base station transceiver (30, 32) and a mobile station (22) and includes information regarding the location of the signal source. A plurality of second locating signals are communicated between a corresponding plurality of ranging beacon devices (40, 42, 44) and a mobile station (22) and each includes information regarding the location of the ranging beacon devices (40, 42, 44). The first and second signals allow for determining the location of the mobile station (22). In a disclosed example, the first and second signals are simultaneously transmitted by the base station (30, 32) and the plurality of ranging beacon devices (40, 42, 44), respectively.

Description

1. FIELD OF THE INVENTION[0001]This invention generally relates to communication. More particularly, this invention relates to facilitating locating mobile communication devices.2. DESCRIPTION OF THE RELATED ART[0002]Wireless communication systems are well known and in widespread use. Typical systems are divided into geographic regions referred to as cells. A base station transceiver provides wireless communication coverage within a cell and typically services several sectors within a cell. There are various communication protocols that are useful within cellular communication systems.[0003]There are various reasons to want to locate a mobile station. For example, emergency 911 services require being able to locate the source of a call for purposes of dispatching response personnel to the appropriate location. Another use of location capability is to locate or track valuable assets whether they are being legitimately carried about or have been stolen, for example. Another use of loc...

AI Technical Summary

Benefits of technology

[0008]An exemplary method of facilitating locating a mobile station includes communicating a first location signal between at least one base station transceiver and a mobile station. A plurality of second locating signals are communicated between a corr

Problems solved by technology

GPS approaches are not useful for all cellular communication scenarios, however, because of the inability for a mobile station to detect enough satellites under various conditions.

For example, in so-called urban canyons and inside of buildings, typical mobile stations (even if they have GPS capability) are not able to detect a sufficient number of satellite signals for purposes of making a location determination.

Under some conditions, therefore, GPS receivers are unable to provide location information.

Even the high-sensitivity GPS receivers that may be able to provide some additional GPS coverage have associated location errors (e.g., 20 meters or more), which are not acceptable for many applications.

One limitation to A-GPS is that the accuracy is typically not significantly better than GPS and may not satisfy the need for precise positioning.

In many situations, a mobile station will not be able to detect weak satellite signals, but may be able to detect nearby cellular base stations.

A potential shortcoming with trying to use this approach is that a mobile station typically cannot simultaneously detect sufficiently strong signals from enough base station transceivers to make an accurate location determination.

Determination of the mobile station's height (altitude) is particularly difficult as the signal sources may themselves not differ significantly in the height dimension.

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